The altitude of 100 km is a magic altitude because it's defined as the beginning of space.

Are there additional magic altitudes like this except the geostationary altitude? If yes a list of these altitudes might be interesting as goals further increasing the XPRIZE CUP competition for maximum altitude. They would be something the public and the competing teams could look at with the question in mind " Who will reach that magic altitude first?" and at least some teams may be struggling for the next magic altitude.

What about magicals concerning maximum number of passengers during one flight, fastest turn-around-time etc.?

The obvious one is ISS orbital altitude. (350km). Even if the X-Cup vehicle doesn't achieve orbital *velocity*, it's still good publicity, and NASA will doubtless make encouraging noises about station replenishment contracts.

Passenger capacity: First vehicle to carry more people in a single launch than the Shuttle does (seven).

Turnaround: First vehicle to turn round in 24 hours. First vehicle to turn round in 1 hour ('kick the tires, light the fires', which Armadillo might actually accomplish).

Thinking of the altitudes asteroids are passing earth I myself too sometimes randomly thinking of this proposal.

But can such an altitude achieved by suborbital flights? I'm doubting intensively. Only the fact that the moon is orbiting and would be falling to earth at a little less speed suggests that suborbital flights to the altitude of the moon at least theoretically are possible. I propose an maximum apogee-velocity to add that is still parabolic or hyperbolic.